Which of the following pairs will give displacement reactions?

Food cans are coated with tin and not with zinc because

$A$ man went door to door posing as a goldsmith. He promised to bring back the glitter of old and dull gold ornaments. An unsuspecting lady gave a set of gold bangles to him which he dipped in a particular solution. The bangles sparkled like new but their weight was reduced drastically. The lady was upset but after a futile argument the man beat a hasty retreat. Can you play the detective to find out the nature of the solution he had used?

What are alloys?

Give an example of a metal which:
$(i)$ is a liquid at room temperature.
$(ii)$ can be easily cut with a knife.
$(iii)$ is the best conductor of heat.
$(iv)$ is a poor conductor of heat.

What would you observe when zinc is added to a solution of iron $(II)$ sulphate? Write the chemical reaction that takes place.